1. Field of the Invention
Aspects of the present invention relate to a cartridge detachably attachable to an image forming apparatus body, and an image forming apparatus using the cartridge.
2. Description of the Related Art
Conventionally, some image forming apparatuses have employed a process cartridge method for integrating an electrophotographic photosensitive member and a process unit operated on the electrophotographic photosensitive member into a cartridge and setting the cartridge to be detachably attachable to the image forming apparatus. The process cartridge method can improve operability by enabling a user to carry out maintenance of the apparatus.
The process cartridge includes a cleaning unit and a development unit. The cleaning unit includes an image bearing member serving as an electrophotographic photosensitive member, and a cleaning member for cleaning a surface of the image bearing member. The development unit includes a developing roller for supplying a developer to the image bearing member, and a developer storage portion for storing the developer.
As one of the process cartridge methods, a developer replenishment method is known. According to this method, a developer replenishment opening of a developer replenishment cartridge and a developer reception opening of the process cartridge are connected to each other, and the developer is supplied from the developer replenishment cartridge to the process cartridge.
In the developer replenishment method, when a new developer supplied from the developer replenishment cartridge mixes with an old developer in the development unit, it may adversely affect an image. Thus, the process cartridge of the developer replenishment method is configured as follows (page 14 and FIG. 4 of Japanese Patent Application Laid-Open No. 2010-014890).
The development unit is divided into a developing portion and the developer storage portion. The developing portion and the developer storage portion are connected to each other by openings formed at both ends of the image bearing member in a rotational axis direction (hereinafter, “longitudinal direction”). The developing portion and the developer storage portion respectively include a developer conveyance member for conveying the developer and a developer stirring member. The developer is conveyed in the longitudinal direction of the developer conveyance member and the developer stirring member. Thus, by circulating the developer in the development unit, the new developer and the old developer are uniformly mixed.
Such a developer replenishment method is configured as follows to stably supply the developer consumed by the process cartridge for forming an image from the developer replenishment cartridge to the process cartridge (page 12 and FIG. 7 of Japanese Patent Application Laid-Open No. 2002-006601).
The developer replenishment cartridge includes a replenishment frame member for storing the developer, a replenishment stirring member for stirring the developer, a replenishment conveyance member for conveying the developer to a developer replenishment opening, and a partition portion for covering the developer replenishment opening and a part of the longitudinal side of the replenishment conveyance member. The replenishment stirring member and the replenishment conveyance member are rotatably supported in the replenishment frame member. The replenishment stirring member stirs the developer in the replenishment frame member, and feeds the stirred developer to the replenishment conveyance member. The replenishment conveyance member conveys the developer to the developer replenishment opening through a developer conveyance portion partitioned by the replenishment frame member and the partition portion, thereby supplying the predetermined amount of a developer to the process cartridge.
In the developer replenishment cartridge, leakage of the developer from the replenishment frame member during a period after its production to its use by the user must be prevented. The replenishment frame member is accordingly sealed by bonding a replenishment opening sealing film to the developer replenishment opening. After this replenishment opening sealing film is removed by the user or automatically removed in the electrophotographic image forming apparatus, supplying of the developer to the process cartridge is enabled.
The developer in the developer replenishment cartridge may be pressed to harden, and then coagulate by vibration accompanying distribution after the production to the use by the user. Especially, when during the distribution, the developer replenishment cartridge takes an attitude so that its longitudinal direction overlaps a vertical direction, and a conveying direction downstream side of the replenishment conveyance member is a bottom surface, the coagulated developer accumulates on the conveying direction downstream side of the replenishment conveyance member. When the developer replenishment cartridge is used in this state, the coagulated developer is further pressed to harden by the replenishment conveyance member, and thus driving torque of the replenishment conveyance member increases. To deal with this driving torque increase, the size of a driving motor may be increased, consequently creating problems of a cost increase and a space increase.